Machine for forming spiral heat exchange coils



3 Sheets-Sheet 1 OrQn Bis/20,061

Charles Cgfilier,

0. BISHOP ET AL MACHINE FOR FORMING SPIRAL HEAT EXCHANGE COILS Feb. 15, 1955 Filed Feb. 26, 1952 w 3 w M y/ H m: w M a M a 9 iv 5 H mow Feb. 15, 1955 BISHQP ET AL 2,702,166

MACHINE FOR FORMING SPIRAL HEAT EXCHANGE COILS Filed Feb. 26, 1952 3 Sheets-Sheet '2 Zhwcntors I Oren BZShqpl Charla; (TM/[0Z3 Feb. 15, 1955 0, BISHOP ET AL 2,702,166

MACHINE FOR FORMING SPIRAL HEAT EXCHANGE COT ELS Filed Feb. 26, 1952 3 Sheets-Sheet 3 if? was 72 1 5% 7 F196. FJQ. 7.

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United States ate'nt MACHINEFOR FORMING SPIRAL HEAT EXCHANGE COILS Oren Bishop, Somerset Center, and CharlesC. Miller,

Addison, Mich, assignors to Addison Products Company, Addison, Mich.

Application February. 26,,1-952,-Serial No. 273,414 Claims. (Cl. 242-82) the feed of the tubing and the spacing wires, and wherein provision is also made for rapidly connecting or disconnecting the inner endofthe coil to a rotatable: forming mandrel.

Theprinciplesof the invention, and the advantages to be derived from the practice thereof, will be apparent from the following description of a practical embodiment, illustrated in the accompanying drawings, wherein:

Fig. l is a plan view, withla iiuished coil. shownon the top of the table;

Fig. 2 is a front" elevation, the work being shown in position at the start of a forming operation; I

Fig. 3 is an enlarged view of the mandrel and guide box, the latter being shown in section;

Fig.4 is an enlarged view from theright of Fig. 3, with portions broken away;

Fig. 5 is an additionally enlarged sectional view, taken substantially on the line 55 of Fig. 3;

Fig. 6 is an enlarged view, partly in section, of a latch and operating mechanism therefor;

Fig. 7 is a view of the inner end'of the latch operating handle;

Fig. 8 is a view looking into the open'end of the-latch oeprating mechanism, showing the latch engaged in full lines, and retractedLin dotted lines;

Fig. 9 is a perspective of the latch element; and

Fig. lO'is an enlarged side elevation of a hold down.

The machine herein specifically illustrated and described is adapted tomake finned" spiral coilsuseful as heat interchangers, such as an' evaporator for a refrigeration ma chine, although the machine isnot limited to the fabrication of this article alone. Referring to Figs; 1, 2, and 5, there is shown in end view, side elevation, and section, the nature of such finned coil. It'c'omprises a length, or two parallel connected lengths, of tubing T having a relatively flat tube portion 21 with integral longitudinal fins 22 along. the narrow dimension, and these fins'have been corrugated lengthwise into a generally sinusoidal config: uration, to provide crests 23, 24', rising above the fiat surfaces of the tubing. Additionally, the crests of the corrugations are reversely depressed adjacent their outer margins, to provide saddles 25. After the stock has been so formed in conveniently continuous lengths, it is operated upon by the present machine, which wraps the tubing into spiral form, and simultaneously introducesspacing wires 26 lengthwise of the tubing, and in the saddles of the fins, where they serve various purposes, including the uniform spacing of the convolutions, and their retention against axial or radial displacement.

For a detailed description of this particular coil, reference is made to the application of Stanley H. Morse, Serial No. 273 ,409, filed February 26,. 1952, now Patent 2,692,119, issued October 19, 1954.

Referring primarily toFigs. 1 and2', the machine comprises a table 31 having a shelf 32 on which are mounted a driving motor 33' having a double ended shaft to one end of which is connected a magnetic brake 34, the details of which form no part of the present invention. The motor may be manually controlled from a switch box 35 on the top 36 of the table, the indicated electrical connections being made in a relay box 37 conveniently posiice 2. tioned on the-shelf 32. The opposite end of the motor shaft is provided with a sprocket over which is disposed a chain 38 extending upwardly through a slot 39 in the top 36, andover the input sprocket'41 (Fig. 4) of a speed reduction unit 42 of any desired type.

The output shaft 45 of the reductionunit 42 extends through-a bearing. pedestal 44, and it hassecured to its end a collar 45-(Eig. 4), to which is welded or otherwise connected a circular backing plate 46, on which in turn is mounted a' slotted and generally spiral mandrel 47t A-bifurcated mounting bracket 48 is po'sitioned'on the left hand side of the table top 35, to support spools 49-of spacing wire 26, and also to support an entrance guide box structure, generally designated by the reference numeral 51. The structure 51' is generally inthe form of a rectangular box havingopen ends, and it 'is pivotally mounted between the legs of the bracket48 by a block 52, welded to the under left hand'p'ortion of the box 51, from which extend trunnions 53- entering suitable bearing apertures in the bracket 48. (See also Figs. 3 and'S). The length of the box is such that its right hand end abuts the rim of the disc 46 when the box opening is substantially tangent to'the mandrel 47, which is the starting position.

As best-shownin Figs. 3 and 5, the guide box 51 comprises a bottom 54 formed with a slot 55 at its forward end, upright side walls 56 and 57, and a hinged top 58 which may be secured in closed position by a hasp 59. Two tracks 61 and 62 are mounted on the'upper side of thebottom' 54, and they are so located with respect to the'dimensions of the tubing T as to abut the surface of the-tube portion 21; when the work is laid fiat in the box; Concurrently, the'outer' edges of'the fins 22 abut the sides of the box and each other-the present guide being adapted to receive twotube' lengths to make a double coil;

A switch 63" is secured to the bottom 54, and it is pro vided with'a pivotedactuatinglever 64having a roller 65 at its end, which projects through the slot 55 andabove an'interrupte'd portion of the track 62. When a length of tubing T is laid in the box on the track 62, and the cover is closed, the roller 65 is depresscd'to close a circuittaken through the switch 63,- a line 66, andrelay box 37, which conditions the switch 35 for manual operation. When the tubing T is removed, as by moving the trailing end thereof out'of the boxand onto the mandrel 47, the lever 64is springelevated'to open the circuit'through the switch 63, thereby opening the motor circuit and applying the brake 34, and overruling the action of the manual switch 35. Hence, at the conclusion of the winding operation, the machine is automatically stopped.

The boxtop or lid 58 is formed at its forward end with four slots 67 having curvedends, each of which is so positioned as to be directly over the line of saddles 25 on either side of the tubing T. The wires 26 are threaded into the slots and are brought forward toward the mandrel 47, and are hooked or otherwise anchored to the ends of the fins 22, as is clearly shown in Fig. 3. When the lid 58 is closed and latched, the wires 26 are pressed into the line of saddles, to hold the tubing T firmly on the tracks 61 and 62. Stated otherwise, the guide box 51 is so dimensioned with respect to the work that, when the work is in position, it is drawn through the guide structure against enough frictionalresistance to insure the positioning of the wires 26 in the saddles 25. The parts of the final assembly of the coil are thus fitted properly together before reaching the mandrel, and additional special drags on the reels 49, or on. the tubing T, are thereby rendered unnecessary.

As bestshown in Fig. 3, the mandrel 47 consists of a piece of metal wrapped initially into a generally cylindrical form, but with the edges spaced radially to provide an entrance slot 71, and thus to conform the shape of the mandrel more to that of a spiral. The forward end or ends of the tubing T may be inserted through the slot 71 to be secured within the mandrel, so that, as the mandrel is rotated, the work will be pulled through the box 51, and wrappedon itself to form a spiral coil. In the embodiment herein specifically described, the work is shown as comprising two parallel. lengths of tubing T, the forward ends of which are connected by a return bend B, from which the fin stock has been removed. This is the part creases.

of the work which is positioned inside of the mandrel, the balance, of course. being wound around the outside.

The work securing mechanism comprises a latch 72 (Fig. 9) pivotally mounted on a bearing 73 disposed on the inner periphery of the mandrel 47 which is spaced from the slot 71. The outer end of the latch 72 is formed with a hook or finger 74, which may be engaged in the bight of the return bend B, and with a tapped aperture 75. One end of outer end of the latch 72 by a screw 77. There is also mounted within the mandrel 47, in spaced relation to the slot 71 and bearing 73, an oscillatable stud 73 which is mounted in a socket dril ed in the back plate 46. The stud 78 is pinned to a concentric bushing 81 at its outer end, and the bushing in turn is axially drilled to provide a pocket 82. in which is secured one end of a rod 83 by means of a set screw 84. The outer end of the rod 83 is transversely dri led to receive a rod 85, by means of whi h the assembly may be rotated.

The bushing 81 is eccentrically drilled and tapped at thebase of the pocket 82, and it is also here formed with a circumferential slot 86. The opposite end of the link 76 is p sitioned throu h the slot, and it is pivotally secure'l within the pocket 82 by a screw 87. The slot is of such arcuate len th that the bushing 81 and attached rods 78 and 83 may be r tated about 180 before the o posite ed es of the link 76 abut the ends of the slot 86. Such rotation m ves the link 76 toward or away from the mandrel slot 71, and thus causes the latch 72 to swing toward or away from the return bend B of the work.

t will be understood that, when the forward end of the t' binq T is positioned through the slot 71 and is secured by the latching mech nism. and the uide box cover 58 is c o ed. the switch 63 wi l be energized, and the mandrel 47 and disc 46 ma then be rotated under the contro f the switch 35. This motion draws the tubing T and wires 26 thr u h the box 51 a ainst the described resistance. and forms the relatively flat length of stock into a spiral c i the diameter of which progressively in- The incoming len th or lengths of tubing. however. are automatically maintained substantially tangent to th coil at all times, as the uide box 51 pivots upward v on its trunni ns 53. This condition is indicated by the broken lines in Fig. 3.

Tt is advantageous. particularly at the end of the winding opera ion. or at times when it may be desired to stop the machine before the coil is completely formed, to pr vide means for h ding the convolutions against possible back lash or slippa e. For this purpose. there is provi ed a sprin actuated hold down, illustrated in Figs. 3 and 10. The bearing pedestal 44 is drilled at its upper end to receive a forwardly extending rod 91 which is threaded at its end to receive a retaining nut 92. A snacing sleeve 93 is positioned over the rod 91. and against its outer end is a collar 94, having plates 95 welded to its ends. The posite ends of the lates are drilled to receive a pin 96 carrying a roller 97. A second roller assembly 98 is positi ned on the rod 91, and between the two is a wrap-aro nd torsion spring 99, secured to the rod 91 by a in 101, and havin its ends 102 and 103 connected to the adiacent plates 95 of the two roller units. A nut 104 on the outer end of the rod 91 retains the parts in position.

At the be inning of a winding operation, the rollers 97 rest on the mandrel 47, and, as the work is coiled, they bear on the fi t surfaces of the tubes 21, and are swung counterc ckwise. as shown by the broken lines in Fig. 3. Alth u h he w rk is under ension. the pressure exerted bv the ro lers aids in forestalling any tendencies for misalignme ts. As previously n ed. when the trailin end of the work passes the rol ers 65 of the solenoid s itch 63, the machine is automatical stopped. The hold down levers then resist any unwindin tendenc while the operator snips the wires 26 below the end of the outermost convolution, works the short tangential end into position, and secures the assembly by suitable means, such as screws sunk through the fins.

It is believed that the foregoing description adequately explains the nature and mode of operation, and that a repetition is therefore unnecessary. It will be seen that the work is properly fed to the winding mandrel, with the edge of one fin abutting the backing plate 46 to assure the formation of a coil whose faces lie in substantially parallel planes. After the coil has been formed, the operator rean operating link 76 is connected to the t leases the latch 72, and the assembly can then be pulled forward to remove it from the machine.

It will accordingly be seen that the present invention provides a simple and inexpensive machine for forming spiral coils, and it is particularly adapted to making heat exchange coils from longitudinally finned tubing, and wherein the convolutions are positively spaced. While the invention has been described with reference to a specific embodiment, it will be obvious that various changes and modifications may be made without departure from its principles. Accordingly, it is intended that the invention be accorded a scope commensurate with that expressed in the following claims.

We claim:

1. A machine for forming spiral heat exchange coils comprising a rotatable mandrel formed as a convolution of a spiral and having the edges of the convolution radially spaced, detachable latch means within the mandrel for gripping the leading end of a workpiece, a guide structure comprising a box having a bottom, sides, top and open ends, a work supporting track positioned within the box on the bottom thereof and between the sides, the width of the box being greater than its inside height, a supporting bracket for pivotally mounting the box adjacent one open end with the other end facing toward the mandrel, means for initially positioning the track of the box approximately tangent to the surface of the mandrel, the top of the box being formed with guide openings on either side of the track of sufficient size to receive spacing wires to be coiled with a workpiece fed through the open ends of the guide box.

2. A machine for forming spiral heat exchange coils comprising a mandrel formed as a convolution of a spiral and having the edges thereof radially spaced, a bearing for mounting the mandrel for rotation about a horizontal axis, latch means within the mandrel and rotatable therewith for securing the end of a workpiece positioned therein between the edges of said convolution, a guide structure pivotally mounted adjacent the mandrel for rotation about an axis parallel to the axis of rotation of the mandrel, said guide structure comprising a box having top, bottom and side walls and open ends, the axis of rotation of said guide structure being positioned adjacent one open end, the opposite open end being positioned adjacent the mandrel and adapted to be substantially tangentially aligned therewith, a longitudinal track in the box between the sides thereof, and parallel slots formed in the box adjacent said opposite open end and on either side of the track.

3. A machine as set forth in claim 2, wherein the guide box track is interrupted adjacent said opposite open end, the bottom of the box is formed with a slot below the interrupted portion of the track, and a depressible control lever is mounted on the bottom of the box to extend through said slot and above the interrupted portion of the track.

4. A machine as set forth in claim 2, further characterized in that the latch is pivotally mounted at one end on the inner surface of the mandrel at a point spaced from the entrance opening, and the latch actuating mechanism comprises a rotatable bushing mounted on the backing plate at a point spaced from said entrance opening and the pivoted end of the latch, said bushing being formed with a circumferential slot, and a link having one end extending through said circumferential slot pivotally mounted within the bushing and its opposite end pivotally connected to the late 5. A machine as set forth in claim 2, wherein the bearing means for the mandrel comprises an upright pedestal having a horizontal supporting rod projecting therefrom above the mandrel, a hold down arm pivotally mounted on the rod, and a spring connected to the rod and arm to urge the arm toward the mandrel and a coil formed thereon.

References Cited in the file of this patent UNITED STATES PATENTS 931,758 Harthan Aug. 24, 1909 1,079,071 Summey Nov. 18, 1913 1,213,771 Leen Jan. 23, 1917 (Other references on following page) UNITED STATES PATENTS Sundh June 26, 1917 Sundh Apr. 9, 1918 Parkes June 24, 1924 5 Wood May 31, 1932 Hoffman Dec. 27, 1932 Bobo Mar. 28, 1933 

